8 basic knowledge of JS that you must pay attention to-JS Tutorial-php.cn

This time I will bring you 8 basic knowledge of JS that must be paid attention to. 8 basic knowledge of JS that must be paid attention to.What are the precautions?. Here are the actual cases. Let’s take a look. one time.

1 Modify the class name of the element in JS: You can modify it through className, but you cannot use class

function toRed() { var tobox = document.getElementById('box1'); tobox.className = 'tmpBox'; }

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2 Function parameter passing

  02-函数传参数

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3 The second method of modifying attributes: (Use when the attribute to be modified is not fixed)

You can use oDiv. style[attribute name] = value; to dynamically modify attributes and values

//括号里放的是变量 function setStyle(propertyName,value) { var oDiv = document.getElementById('div1'); oDiv.style[propertyName] = value; }

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4. The difference between style and className

##Element.style.Attribute = xxx; is the modified interline (inline) style, and its priority is relatively high!!! For example: oDiv.style.backgroundColor = ' red';

className: You can find the corresponding style by specifying the class name;
But if you use style and then use className to specify the style, it will have no effect!!!!

Note: Either use style to set the style, or use className to specify the style alone. They cannot be mixed, and unknown errors will occur!

5.提取行间事件

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window.onload The

behavior will be executed only after the page is loaded. Separation of style and structure: JS CSS HTML separation

Extract events

Add events to elements

  05-提取行间事件

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6.JS gets child elements from parent elements

Get the input from the code below

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and put it down as follows:

window.onload =function (){ var oDiv = document.getElementById('box1'); //现获取父元素div var inputs = oDiv.getElementsByTagName('input'); //再通过div获取到里面所有的input}

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7. innerHTML

is used to set the container The content of the tag can be text or HTML (tag).

  08-innerHTML

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8. String splicing:

var str = '我叫小明'+12+'岁'+168+'2017'; >>> 结果:我叫小明12岁1682017var num = '9+6等于'+(9+6); >>> 结果: 9 + 6 等于 15

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I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the php Chinese website!